暴风雪对自由空间量子通信信道的影响及性能分析

Influence and performance analysis of snowstorm on the free space quantum communication channel

为了研究暴风雪对自由空间量子通信信道的影响,根据暴风雪的物理性质,将暴风雪的强度分为4个等级,首先提出了暴风雪天气等级与自由空间量子信道衰减的关系;针对退极化信道和相位衰减信道,分别建立了不同等级的暴风雪天气与信道纠缠度、信道保真度的模式方程;最后,分析了不同等级暴风雪对量子信道可用时间利用率的影响。数值分析及仿真结果表明,当暴风雪天气等级由1增加到4时,自由空间量子通信信道衰减由0.9增加到13;信道纠缠度由0.93减小到0.25,保真度由0.97衰减至0.85;信道的可用时间利用率由0.88降低到0.37。因此,为了提高自由空间量子通信的可靠性,应根据暴风雪天气灾害程度,自适应调整系统的各项参数。

In order to investigate the influence of snowstorm on the free space quantum communication channel,the physical characteristics and the grades of snowstorm should be analyzed first. According to the physical parameter and the degree of the snowstorm weather,the relationship between the snowstorm weather and the channel attenuation of the free space quantum communication can then be proposed. According to the depolarizing channel and the phase fading channel,the effects of different grades of snowstorm weather on channel entanglement and channel fidelity are established. Finally,the effects of different grades of snowstorm weather on the available time utilization rate of quantum channel are put out and simulated. Simulation results show that,if snowstorm weather rating increased from 1 to 4,the channel attenuation of the free space quantum communication is increased from 0. 9 to 13,the channel entanglement is reduced from 0. 93 to0. 25,the channel fidelity is reduced from 0. 97 to 0. 85,and the available time utilization rate of quantum channel is reduced from 0. 88 to 0. 37. Further more,the channel fidelity has an obvious difference between the two kinds of channel,which is related to the rotation angle or not. Thus,the grade of the snowstorm weather has a significant effect on the free space quantum communication channel. And,in order to improve the reliability of quantum communication in free space,the parameters should be adjusted adaptively based on the status of snowstorm weather.